This invention relates generally to a surgical cutting accessory that is used to cut tissue and, more particularly, to a surgical cutting accessory with a nickel titanium alloy cutting head.
One component that is an integral part of many surgical tool systems is the cutting accessory. This cutting accessory is a device that is typically attached to some sort of driving unit. Often, but not always, the driving unit is some type of handpiece that contains an electrically or pneumatically driven motor. The cutting accessory is an elongated member that extends from the handpiece. The distal end of the cutting accessory, the end furthest from the surgeon, is shaped to define a cutting head. In order to remove tissue, the surgeon actuates the handpiece and applies the cutting head of the accessory to the tissue to be removed. If the tissue being cut is bone, the cutting head is used to form a bore in the bone or to otherwise shape the bone.
Often cutting accessories are fabricated from stainless steel. Advantages of making an accessory out of this material are that it is relatively economical to provide, the steel can be shaped to define the sharp cutting surfaces of the head, and it can also withstand the rigors of post manufacture sterilization without physical degradation.
Nevertheless, there are some disadvantages associated with providing cutting accessories with cutting heads formed from steel. Specifically, steel is relatively rigid. Consequently, when a cutting accessory with a steel head is pressed against bone, the surgeon may have to precisely hold the accessory against the bone so that it does not bend significantly relative to the longitudinal axis of the bore being formed. If there is significant deviation from this axis, the cutting head may not be able to withstand the stress.
This invention relates to a new and useful surgical cutting accessory. In one version of the cutting accessory of this invention, the accessory is provided with a shaft formed from stainless steel and a head formed from a metal that has more flexibility than the stainless steel. In some preferred versions of this invention, the material from which the head is formed is a nickel titanium alloy. This head may be a drill tip, a bur head or open ended tubular member that forms part of a tissue cutter. In alternative versions of this invention, the whole of the cutting accessory, its shaft and head, are formed from material that has a greater degree of flexibility than stainless steel.
In still other alternative versions of the invention, a cutting accessory may have a shaft that comprises one or more sections of rigid material like stainless steel and one or more sections of a more flexible metal or metal alloy such as the nickel titanium alloy. In some embodiments of these versions of the invention, the shaft is formed substantially of steel, has a distal end neck formed of the more flexible metal or metal alloy and a cutting head formed of steel.